FERRITIZATION TREATMENT OF MERCURY-CONTAINING WASTE WATER

PURPOSE:To remove and recover efficiently in mercury-contg. waste water by adding a soln. contg. Fe to the waste water, aerating the waste water after adjustment of pH then adding a reducing agent thereto to reduce and evaporate the mercury ion in the waste water to metallic mercury. CONSTITUTION:The soln. contg. Fe is added to the mercury-contg. waste water and the pH is adjusted to 10-12 by an aq. alkali soln., then the waste water is aerated and after the ferritization reaction is completed, the reducing agent such as hydrazine or the like is added to the waste water to reduce and evaporate the mercury ion in the waste water to metallic mercury. The evaporated mercury is discharged together with waste gas and the mercury is recovered by cooling and scrubbing of the waste gas and absorption by an acid. As a result, the mercury in the waste water is surely and efficiently removed and recovered, by which the concn. of Hg ion in the waste water is decreased down to